Fiber optic cable is the best choice for long-distance telecommunications and high-speed data connections. While most telephone and cable companies now use this high-tech cabling, there are still areas working to upgrade the existing carrier infrastructure. These cities must bury thousands of feet of cable as efficiently as possible to make the transition to higher-speed communications. Trenchless technology can assist in this upgrade.

Why Use Trenchless Technology for Fiber Optic Installation

Traditional methods for laying fiber optic line require the digging of a trench to place the wires. While that is the default choice for many municipalities, it is not the most cost-effective option. Trenchless methods are faster and therefore cost less. It also takes a smaller crew, saving money on payroll hours. (For more on cost, see Studies Claim the Trenchless Construction Cost Comparison is Massive.)

In addition to saving the city’s bottom line, trenchless technology offers a safer method of fiber optic installation. While residents must use caution, as with any type of construction work, there are no significant trenches for them to trip into. Walkways and driveways remain undisturbed, reducing the number of hazards within the neighborhood.

Trenchless installation of fiber optic lines also minimizes the impact on the surrounding environment. Less earth is disturbed, meaning wildlife habitats are not destroyed. It also decreases surrounding air pollution by not stirring up dust and debris.

Challenges Faced During Installation

As with any construction work, trenchless installation of fiber optic lines faces challenges not posed by traditional trenching methods. One of the most hazardous of all obstacles are existing underground utility lines. While all utility companies willingly mark the location of their subterranean lines, there is always a chance that something is mislabeled, or a request for line marking is forgotten.

While ensuring there is no damage to underground utility lines is a priority, there are other underground hazards that occur. Small rocks are not an issue for most trenchless methods. However, larger rocks can impede progress in drilling the necessary pathway. A survey using ground penetrating radar can alert planners to potential issues. However, these readings may be misinterpreted, causing further delays or damage to equipment.

Soil conditions also play a role in determining how to proceed with trenchless installation efficiently. Soft soil could cause borehole collapse after excavation if a suitable pipe is not in place. Conditions of the underlying dirt can also cause problems for the line once it is in place due to settling. (To learn more on soil conditions, see Soil Types and How They Affect Trenchless Construction.)

A final challenge faced by trenchless construction workers is natural obstacles. While most fiber optic cable installation is in commercial or residential areas, there may be canals, streams or even rivers with which to contend. Project planners must determine the best method of traversing these barriers before beginning installation.

Trenchless Methods of Fiber Optic Installation

Different trenchless methods are available for installation of fiber optic lines. The simplest way is to use current underground infrastructure. Fiber optic wires can run alongside, or as a replacement for, other phone or cable lines inside their existing tubing. Workers only need to dig access points to pull the wire in place.

When soft or medium texture soil is a consideration, it is best to employ direct burial methods. With this method, a plow goes through and loosens the ground to lay the cable. By preplowing, operators can determine if there is any underground obstruction, such as a large rock or previously unmarked line. The fiber optic line is then fed into the plowed area by a skilled technician.

The use of a mole tool allows crews to stitch the fiber optic lines underground. This method requires a small access pit about 20 to 24 inches wide. The operator enters the hole with the mole and shoots the device into the dirt. Corrections to the mole placement are made at the beginning, if necessary. Once on target, the operator leaves the mole to dig and pull the cable in place. As with the plowing technique, the stitch direct burial method works best in soft to medium-hard ground conditions.

A final trenchless method for installing fiber optic cable is horizontal directional drilling or HDD. HDD is optimal in areas with rocky or hard ground conditions, as the boreholes are less likely to collapse in on themselves. For HDD success, operators must know the location of all subterranean utility lines before beginning. With the directional drilling method, the drill bores a pilot hole along the predetermined path. After completing the pilot hole, workers ream the borehole and pull the new cable through. Because there is no surface disturbance, HDD is the best choice to run fiber optic cables under sidewalks, streets and structures.

While traditional trenching techniques are necessary for some projects, upgrading and installing new fiber optic cable is not one of those times. The use of trenchless methods offers a safer job site and faster installation, allowing workers to lay more cable in a shorter amount of time.